Marshmallow Addiction
by dazai-san
Summary: The new DADA teacher is weird. He has a marshmallow addiction. He's ridiculously misleading. He loves teasing. He… he's not even teaching them magic! Dumbledore might've wondered if Dolores Umbridge was a better choice for this year's DADA teacher if it weren't for the fact that he picked Byakuran because of aforementioned traits. (The transfer students aren't any better.) TYL
1. Chapter 1

**Title:** Marshmallow Addiction

 **Rating:** T

 **Genres:** Humor, Friendship, Romance, Adventure, mild Hurt/Comfort and Angst

 **Summary:** The new DADA teacher is weird. He has a marshmallow addiction. He's ridiculously misleading. He loves teasing. He… he's not even teaching them magic! Dumbledore might've wondered if Dolores Umbridge was a better choice for DADA teacher if it weren't for the fact that he picked Byakuran because of aforementioned traits.

 **Pairings:** 10069100, 2759, XS, R56, 18D; others undecided.

 **Warnings:** Swearing, violence, hilarity in general, crude humor, spoilers, post-manga, possible OOC, _Byakuran_ , TYL, the works.

~oOo~

Dumbledore's first impression, after he's pulled off the blindfold?

He's _impressed._ The Vongola mansion he's visiting is about half the size of Hogwarts, and this is only one of their minor branches. And it's beautifully decorated, while men and women alike mill about, talking animatedly about their day.

Not exactly the kind of thing you'd expect from the mafia, but he's heard rumors of the Vongola Decimo's extreme kindness.

As he walks towards the gate, a silver haired young man, perhaps twenty-three or twenty-four, chewing an unlit cigarette, looks up at him with guarded but seemingly disinterested green eyes, their color vivid like young Harry Potter's.

From the look of him, he looks slightly Asian but mostly Italian, although the hair color is a little misleading.

"Albus Dumbledore-san?" the young man asks, tilting his head. He's most likely part Japanese then, Dumbledore decides, since he uses an honorific.

Upon hearing his name, Dumbledore nods and says their meeting phrase: "Storm, rain, sun, lightning, cloud, and mist."

"They are all powerful, but cannot exist without a sky," the man replies in flawless English, and Dumbledore is, yet again, very impressed. "Welcome to one of Vongola's Scotland branches. I am Hayato Gokudera, the Storm Guardian and the right hand of the Vongola."

Dumbledore, to be honest, is rather flattered that Decimo has sent his right hand man to greet him. He follows after Hayato, who's turned and is leading him into the mansion. People around them turn to the young man, dipping their heads in respect.

They reach the dining hall, where Hayato kicks the door down, startling Dumbledore quite a bit but he manages not to show it as he follows him into the room.

It's _large_. And there's no grand table or anything; just small tables and the such scattered all around and Dumbledore looks around in slight confusion as he wonders where the Decimo and his guardians sit.

Reading his expression, Hayato rolls his eyes. "The Decimo and his Guardians don't sit together at one big table. We sit with whomever we like, and everybody knows that they can feel free to take a seat anywhere they'd like. The Decimo's kind like that."

Dumbledore watches as several people, around Hayato's age, come in, dragging a huge table, and taking out the others. "But today's a special occasion," Hayato adds. "Since you're here, the Decimo thinks it'd be nice to invite you for dinner to discuss the mission details with the core members of the Vongola."

"I'm… flattered," Dumbledore tells Hayato sincerely.

A tall tanned man comes over, a bamboo sword on his back before Hayato can reply. "Ah, is this is our client?" he asks with a Japanese accent.

"Yes, you dumbass," Hayato retorts, rolling his eyes. "Dumbledore-san, this is Takeshi Yamamoto, but feel free to call him baseball nut. He's obsessed. And he doesn't take offense."

As if to prove his point, Takeshi just grins widely before pointing to the seat next to the largest one. "You're sitting there," he says. "It's just so conversation is easier… and you're also safer there. And Gokudera likes sitting on the right side."

 _Safer…?_ Before Dumbledore can question it too much, he's being shoved towards the seat as others start flooding in, and they are quite… _odd_ …

Just like Takeshi said, Hayato takes a seat on the right hand side of the head of the table, where the seat is still empty. Takeshi takes the seat next to Hayato, quickly waving over another pale-haired man, maybe a little older than Takeshi and Hayato, but this one's louder.

"Are you extremely our client?" the man booms energetically. "If you are, I am the extreme Sun Guardian, Ryohei Sasagawa! It is nice to meet you to the extreme!"

"Sit down, senpai," Takeshi laughs. But before Ryohei does, a poker faced and black-haired man practically glides in.

For some reason, the young man gives him the chills, but Dumbledore suppresses the feeling. But Ryohei seems to lack survival skills and as soon as he spots the man, he smiles even wider. "Hibari!" He prances towards him and latches onto his arm, practically dragging him over to his seat. "This is Kyouya Hibari to the extreme, our Cloud Guardian! This is our client!"

"Stuff it, herbivore," Kyouya deadpans, taking the seat right next to Ryohei. "And don't touch me, or I will bite you to death. Also, I know who he is. If the _smarter_ herbivore let him in, he's clearly our client."

Hayato grunts. "Well, thank you _so much_ for the compliment, you stick in the mud." Kyouya ignores him.

Another white haired man comes in, but he has odd lavender eyes, and a purple mark under one of them. He blinks, stares at Dumbledore for a moment, before taking the seat next to him. "Would you like a marshmallow?" he asks, proffering Dumbledore a bag.

Dumbledore takes one. "Thank you mister…?"

"Just Byakuran's fine," the man replies cheerily. "I don't have a surname."

Suddenly the doors slam open again, and a motley rabble of loud people enter. Louder than Ryohei, if that's possible.

"VOOOOIIIIII!" screams a long white-haired man. (Seriously, what is up with these people and white hair?) "ARE WE LATE?"

"Who cares if we're late, trash!" roars another, throwing a wine glass at the other's head, and it splinters. "We don't give a shit about these guys! Besides, the Decimo ain't even here yet!"

"SHUT UP, SHITTY BOSS!"

Byakuran giggles. Yes, _giggles._ "Those are the Varia, the elite assassin squad of the Vongola," he tells Dumbledore.

"The loud one who's shouting 'butter' in Finnish is Superbi Squalo. Just call him Shark or Squalo, and he's the Rain Guardian and the right hand. The one with all the scars is Xanxus; he's the boss of the Varia. You see that guy with the permanent deadpan and the ridiculous hat? That's Flan; he's their Mist Guardian."

Then he sees a blonde shoving knives into the hat. Dumbledore watches in surprise.

"Oh, we're all used to it," Byakuran assures. "Flan got a trident shoved through his head, don't worry too much. The blondie is Belphegor, and he's the Storm Guardian; just call him Bel. And you see those two weirdos in the back? The one ogling Xanxus is Levi, the Lightning Guardian, and the clearly gay guy is Lussuria, their Sun Guardian."

Xanxus marches over to the other head of the table, plopping down in the seat and looking grouchy as Squalo sits on his right side, Levi sitting on the left. Before they get too clear on the seating arrangements, a purple haired man with a low ponytail saunters into the room, followed by a young girl with a similar pineapple hair style.

Kyouya, for some reason, glares at him.

"That's Mukuro Rokudo, and the girl is Chrome Dokuro," Byakuran informs him as he waves over the pair, and Mukuro takes a seat next to Byakuran, Chrome taking the next one down. "Hibari-kun and Mukuro have a terrible relationship, isn't that right?"

Mukuro just smirks and Dumbledore realizes he's heterochromatic, with one eye red, the other blue. "Kufufu… the little skylark is pathetic… he doesn't realize he'll never bite me to death. And birds don't have teeth, at any rate."

Kyouya glares at Mukuro and growls.

"Ah, Mukuro-shishou," Flan says in a monotonous voice. "You're here." He takes a seat next to Chrome, while Belphegor takes the open seat next to Flan. Flan doesn't seem to realize there are three knives sticking out of his head.

The door opens again, and a blonde walks in, smiling brightly, before promptly tripping over his own feet and falling face first on the ground. Kyouya, upon seeing him, raises an eyebrow before standing up and pulling him up. "You're pathetic," he tells him.

"Haha, Kyouya! I knew you missed me!"

"Keep talking like that, and I'll be handing you a one way ticket to hell."

"The clumsy blonde is Dino," Byakuran says. "He's absolutely hopeless unless one of his Famiglia members is around. He's actually part of the Cavallone Famiglia, but he's almost Decimo's older brother, so he's invited."

Kyouya walks Dino to his seat, kicks him in (which the blonde still falls out of) and returns to his seat between Dino and Ryohei.

Dumbledore tries to prevent himself from staring. "Is it possible to be that clumsy?"

"Apparently," Mukuro says, still smirking.

Finally, Lussuria takes a seat next to Squalo, clearly much to the white-haired man's discomfort.

Suddenly, a group of fifteen year olds led by a pair of thirty year old and twenty year old young women enter the room. A teenager with a fedora takes a seat next to Dino, a blonde wearing an army outfit joining him after exchanging greetings with Ryohei.

"The man in the fedora is Reborn, the Sun Arcobaleno, and the blonde is Colonello, the Rain Arcobaleno," Byakuran says, gesturing at the two who're now arguing with each other. "The thirty-year old scary lady sitting next to Colonello is Lal Mirch, the one with the Corrupted Pacifier, and Yuni-chan is the girl sitting next to her, the Sky Arcobaleno."

Indeed, Lal Mirch does seem incredibly terrifying.

"The Hibari-kun lookalike sitting next to Belphegor is Fon, our Storm Arcobaleno. The not-female hooded one is Viper, the Mist Arcobaleno, but he prefers Mammon. The scientist one is Verde, our Lightning Arcobaleno."

Byakuran tilts his head slightly. "So, I think we're missing our Lightning Guardian, Lambo, Ranking Fuuta, Basil, and I-Pin. Since Kyoko-chan and Haru-chan aren't actually part of the Famiglia, they won't be coming; Shoichi and Spanner are in Italy, so they can't come either… and the last of the Arcobaleno, Skull, the Cloud Arcobaleno, is hiding from Reborn and Colonello. Can't blame him, though."

The door opens, and it's a brown-haired young man with sea blue eyes, leading a group of teens into the room. "And that's them!" Byakuran exclaims. "Basil-kun is the blue eyed one, Fuuta is the younger brunette, I-Pin-chan is the cute little girl, and Lambo-kun is the curly haired boy."

As soon as I-Pin sits next to Yuni, Lambo next to her, Fuuta next to him, and Basil across from them, the door opens, and the Vongola Decimo enters.

"Sorry I kept everyone waiting!" the brunette calls with a slight Japanese accent, smiling warmly. "I had to clear up a couple of misunderstandings with the rest of the people here; they understood of course."

"It's no problem, Juudaime," Hayato replies, and it's clear that the poor boy is infatuated with his boss.

"Of course they would," Xanxus grumbles. "We're scary as shit, man. We're the fucking _Varia._ "

The Decimo takes his seat, smiling warmly at Dumbledore. "I'm Tsunayoshi Sawada; a pleasure to meet you, Albus." And to Xanxus, he merely smiles slightly. "Xanxus, I'm going to have to ask you to cut down on your attempts at being badass. While it works, you also triple your terrifying appeal every time, and you end up scaring my subordinates."

Xanxus rolls his eyes. "Put a sock in it, trash. I don't give two shits about what your subordinates think of me."

" _Xanxus_. Do we need a repeat of the Crib incident? Or, the Cradle Incident, if you'd like."

Xanxus blanches. "No. No sir."

Squalo cackles loudly, resulting in Xanxus picking up an empty wine glass and smashing it over his head. Dumbledore winces.

"Don't worry about it," Tsunayoshi says, smiling quite cheerfully. "This happens every time. Unfortunately, we end up scaring our clients a lot. I hope you're used to insanity."

Dumbledore laughs. "I certainly am, being the Headmaster of a school of magical children."

"That's great," Byakuran pipes up. "Because as soon as the food is served, something will be set on fire. What was it last time, Tuna Fishie?"

"I think it was the punch," Tsunayoshi replies after thinking a little. "Don't even ask how a bowl of _punch_ got set on fire."

"No, Juudaime," Hayato corrects patiently. "That was the time before last time. Last time it was the roast pig."

"Ah, thanks, Gokudera-kun."

True to Byakuran's word, as soon as the food is served, the pasta is set on fire.

"Hah!" Hayato cries triumphantly. "Yamamoto, you owe me twenty euros!"

Takeshi sighs and tosses it on the table, which Hayato collects.

Byakuran reaches for the pitcher of ice water before dumping it over the pasta, most of the noodles already turned to ashes.

So while Dumbledore attempts to hold a conversation about the mission he wants to give to Tsunayoshi, the other parts of the table are in chaos.

"So, Decimo, you've done dealings with wizards before, am I right?"

"Yes," Tsunayoshi nods. "And you can call me Tsuna if you'd like, Albus."

"Alright. Tsuna, then. I'd like a teacher for my school, to take up the position of the Defense Against the Dark Arts."

Tsuna blinks. "We can't do magic though."

"Yes, but I'd like a teacher who's focused more on the physical part of training," Dumbledore replies. "And also, the Ministry's been breathing on my neck the entire summer."

"Ah, I see. Politics, then?"

Dumbledore nods helplessly.

"I feel _so_ bad for you," Tsuna groans. "I hate politics. Sure. Take one of the people here; I'll make them go if they don't want to; pick anyone."

Dumbledore is shocked. He thought he'd need a lot more convincing to do. "How much would you like for the payment?"

"Actually, Albus, just keeping silent about us and taking a guy or two would be payment enough," Tsuna says with a pained smile. "They're insane. Ten or so months away at school would mellow them out."

Tsuna pauses. "Wait. Take all of the Arcobaleno. Please. Make them students. _I beg you._ With the exceptions of Lal and Yuni."

A little surprised, Dumbledore nods dumbly.

"Thank you. So, who are you taking? Please don't say it's Gokudera-kun. I need someone to keep me sane."

Poor Hayato, Dumbledore muses. He probably would love to hear that coming from his boss's mouth, but he's too busy yelling at Takeshi.

And actually, Dumbledore has considered Hayato. "No," he decides, shaking his head. "Would Byakuran be a good choice?"

Tsuna spits out the water he'd been drinking before breaking out into giggles.

Dumbledore waits until Tsuna has recovered. "Yes. Please do. It will make Reborn's life hell, having to listen to _Byakuran_ of all people."

"Alright then," Dumbledore decides. "I'll take him."

Tsuna insists that he stay for dinner, and the food is certainly excellent. But it's nothing compared to the entertainment.

First, Xanxus tosses a slab of raw steak (where did that even come from?) at Squalo, and the Varia Rain glares at his boss before plucking the meat off his head and tossing it across the room.

That causes Belphegor to throw knives at it to practice his aim, and the poor slab of meat ends up with three knives buried in its side.

That causes Lambo to look down at his cow print shirt self-consciously before hiding under the table, which causes I-Pin to crawl under with him, but her braid slaps a sharp knife into the air (somehow) and it lands straight in Kyouya's sushi, which causes him to look around dangerously and proclaim that he'd bite whoever did that to death.

And that causes Dino to stand up and try and drag Kyouya down, but somehow ends up tripping onto the table, sending food flying.

Needless to say, a food fight broke out, while Tsuna, Dumbledore, Basil, and Byakuran just watch as it disintegrated into chaos.

Dumbledore now understands why Takeshi had said that hanging around Tsuna is safer.

~oOo~


	2. Chapter 2

**Title:** Marshmallow Addiction

 **Rating:** T

 **Genres:** Humor, Friendship, Romance, Adventure, mild Hurt/Comfort and Angst

 **Summary:** The new DADA teacher is weird. He has a marshmallow addiction. He's ridiculously misleading. He loves teasing. He… he's not even teaching them magic! Dumbledore might've wondered if Dolores Umbridge was a better choice for the DADA teacher if it weren't for the fact that he picked Byakuran because of aforementioned traits. (The transfer students aren't any better.) TYL

 **Pairings:** 10069100, 2759, XS, R56, 18D; others undecided.

 **Warnings:** Swearing, violence, hilarity in general, crude humor, spoilers, post-manga, possible OOC, _Byakuran_ , TYL, the works.

~oOo~

"Now, now, children, don't look at me like that," Byakuran chides. "This _is_ Tsunayoshi-kun and Dumbledore-san's idea… I don't want to be teaching brats, myself."

Reborn considers. "I suppose," Reborn concedes grudgingly. "But I'm not listening to you unless it is absolutely necessary."

"I second that, kora!" Colonello calls, kicking his feet childishly.

"Me too!" Skull pipes up.

"I do as well," Viper and Fon say at the exact same time, while Verde blinks in boredom. "Yeah, me too," he adds a moment later.

They're sitting in a train compartment, bored out of their minds. Except for Byakuran, because he's reading a very long book.

"And we are _not_ wearing this ridiculous uniform," Viper announces out of the blue.

"I agree," Fon huffs, waving a long sleeve in annoyance. "It's hardly conventional, and I just _know_ it'll be hard to move in. And it tears easily." As if to prove his point, Fon picks up the robe and rips part of the sleeve without any difficulty.

"Well, at any rate, I'd rather wear this than a dress, kora," Colonello says mournfully.

All of the Arcobaleno smirk. Byakuran blinks. "Is this about the Dress Incident you guys keep mentioning?"

Viper nods. "It was so embarrassing for him. I actually might've thought he was a girl."

"S-shut up assholes, kora!"

Reborn just smirks and pulls out seven different copies of _Romeo and Juliet_ , all in different languages.

Nothing really exciting happens for the rest of the trip.

~oOo~

"Wow," Reborn comments. "Nice steeds they've got here."

Colonello pats one on the head gently before climbing into the carriage, joined by the rest of them. It's a bit cramped, Byakuran decides, but not too bad.

Hogwarts is very large and majestic, but nowhere near as awesome the actual Vongola Mansion. Byakuran leads his "students" up the stairs, heading into the Great Hall.

Loudly, just to humiliate the Arcobaleno, he announces, "Now, behave yourselves, children! We all know what happens when you're left unsupervised!"

"Go die, Byakuran, kora!" Colonello snaps back hotly.

"Are you a voyeur or something?" Viper asks, deadpanning. "Of course, I wouldn't put it past you."

Byakuran smirks. "That's for you to wonder, and for me to know." Then he proceeds to skip (yes, _skip_ ) to the staff table, taking a seat.

Clearly disgruntled, the Arcobaleno take a seat with the first years, ignoring the curious glances they get. After Minerva McGonagall sets a hat on the stool, she steps away, and the hat begins to _sing_.

As soon as it's done, Byakuran puts his hands together in applause. Not for White Applause, of course.

Then students are one by one called up to the stool, and soon, the Sorting Hat screams out a name and the student would be sent to the corresponding table.

As soon as all of the students are Sorted, Albus stands up, clapping loudly once. "Clearly, as you can see, the last students to be Sorted are not first years," he begins. "They are this year's transfer students, who go under the name _Arcobaleno_. However, they will not actually participate in class; they are merely there to observe."

Reborn tilts his fedora. Colonello gives a lazy wave. Viper does nothing. Skull huffs and slouches. Verde practically falls asleep. Fon covers his yawn with a sleeve.

"Please give them a warm welcome."

Polite clapping sounds all around the room, and Byakuran catches Reborn glaring at him suspiciously as he claps.

"Since they don't have surnames, we'll be calling them up by their first names," Minerva continues for Albus as he takes a seat. She stands, and holds the list.

"Colonello, please come up."

The blonde doesn't even bother hiding his yawn before taking a seat and tossing the Hat on his head.

After about ten minutes of waiting, the Hat finally shouts out, "GRYFFINDOR!"

The house of red and gold bursts into cheers, and Colonello gingerly takes off the hat before putting it back on the stool and heading towards the table, where a pair of twins manhandle him next to them.

Once the clapping has died down, Minerva clears her throat. "Fon!"

Gracefully, Fon strides towards the stool, sitting down and putting the Hat on. After a considerably shorter amount of time (five minutes), the Hat shouts: "HUFFLEPUFF!"

Clapping comes from the Hufflepuff table as Fon heads over. Then Minerva calls out Reborn's name.

Reborn walks stiffly to the stool, clearly disliking the fact that he has to take off his beloved fedora. After about two minutes (clearly the Hat is terrified of Reborn), the Hat screeches, "SLYTHERIN!"

Immediately Reborn heads to the table, replacing the fedora on his head.

"Skull!"

After another five minutes, the Hat shouts, "SLYTHERIN!"

At this proclamation, Reborn grimaces and Colonello bursts out cackling while Skull looks terrified, going to the far end of the table, and away from Reborn. Byakuran smiles in amusement, chewing on a marshmallow.

After the phase passes, Minerva calls up Verde.

Almost as soon as the Hat is placed on Verde's head, the Hat shouts, "RAVENCLAW!"

"Huh," Byakuran says aloud. "That obvious?"

Then Viper stands up at the same time Minerva calls out his name, gliding over to the Hat.

After about three minutes, the Hat calls, "SLYTHERIN!"

Minerva rolls up the scroll before taking her seat again, and Albus announces for them to start eating, food appearing out of nowhere on the table.

Byakuran, due to the fact that he has a need to travel a lot for missions, finds nothing on the table out of the ordinary, except for the fact that the food is far richer than he'd expected.

Seriously. _How are these children not obese?_

Once the food has disappeared, Albus stands, clearing his throat for a speech.

"Well, now that we are all digesting another magnificent feast…" Byakuran pretends that he's listening, while in reality, he's actually mentally calculating how much force he'll need to put on a marshmallow if he wants to fling it into the nearest wall and make it stick.

"…to welcome back Professor Grubbly-Plank, who will be taking Care of Magical Creatures lessons; we are also delighted to introduce Professor Byakuran, our new Defense Against the Dark Arts teacher. We will also be receiving a wonderful Supervisor this year, but unfortunately Professor Dolores Umbridge will not be available until tomorrow…"

A round of polite applause comes around the room, and Byakuran once again tunes Albus out, this time fingering a butter knife and wondering whether he'd be able to get away with throwing it at the opposite wall and making it stick.

Then again, Byakuran can get away with practically _anything_. So when Albus is about almost done, Byakuran throws the butter knife with blinding speed, and a loud _thunk_ startles the majority of the people in the room into silence.

"Oops, my bad," Byakuran says, smiling quite cheerfully and not sounding apologetic at all. "Please do continue with your speech, Albus."

"That, I will," Albus replies, sounding amused, and indeed he does… which Byakuran once again tunes out.

And suddenly the clattering of plates and the such alerts Byakuran to the fact that Albus has dismissed the students. Byakuran stands, stretches, and yawns, his White Dragon who he had so creatively dubbed Shiro, rocking in its box.

Then he leaves for his room, waving cheerily at his "students" just to annoy the Arcobaleno.

~oOo~

Byakuran, upon having a nice breakfast, heads up to his _very_ large classroom and bedroom, so kindly enlarged by Albus. He's set up a variety of weapons all around the room, and some harmless traps on varied chairs that are rather obvious, at least for him.

And on every single desk, he's placed a perfectly harmless marshmallow.

On the board, he's written in loopy writing "Welcome to Professor Byakuran's _Super Fun and Perfectly Safe_ DADA Lesson!"

Perfectly safe, his ass.

But the children don't have to know that.

He can't wait for his first fifth year class (since the Arcobaleno are fifth years), sighing internally as the door slams open, and a group of third years screech as white paint drips onto their heads.

~oOo~

Harry, already annoyed with how his day's been, is even more incensed when something conks over his head as soon as he opens the DADA classroom door.

Colonello, the only one in the room apart from Harry, Ron, and Hermione, smirks at them in amusement, and Harry realizes that Hermione and Ron are rubbing their heads in annoyance.

"What're you laughing at?" Harry snaps at the transfer. "Don't act like _you_ didn't get hit in the head too!"

"Actually, I didn't get hit, kora," Colonello replies smugly. "My house back in Italy is full of traps, and Verde likes updating them every other hour, so I have to know how to detect and avoid them, kora. It's Verde's idea of a joke, kora. And I'm not laughing, kora."

Harry huffs in annoyance before heading over to Colonello, but a sudden cloud of rainbow powder exploding under his foot stops him, the powder billowing up around him and his two friends.

"What the bloody hell was that?" Ron coughs, and much to Harry's relief, the powder doesn't stick to their skin.

Harry's eyebrow twitches as he takes the seat in the front next to Colonello, Ron taking the other open side, and Hermione next to Ron.

Unfortunately for the three of them, the seats are rigged as well. As soon as Harry sits down, a bucket of hay is dropped on his head, and as Harry dusts it off, he sees Byakuran watching them with no little amount of amusement.

Poor Ron gets Halloween decorations dunked on him, and while it is certainly amusing seeing Ron panic at the sight of a few fake spiders, Harry feels sorry for him. Hermione gets a glass of milk upturned on her head.

As other students walk in, Harry sees various other traps being activated. As soon as Lavender and Parvati step in, they shriek as they're immediately soaked in milk. He feels some satisfaction at this. He sees one boy get a stuffed squeaky mouse dropped on his head, and another getting launched off the seat from some pretty super powered confetti.

Once the bell has rung and the seats have been all taken, Byakuran stands up, clapping his hands and smiling cheerfully. At this point, Colonello is the only who's clean.

"Ko-ni-chi-wa!" Byakuran calls out, waving. "That's good afternoon in Japanese, by the way. Welcome to my super fun and exciting class! Feel free to eat the marshmallow on your desk. It's perfectly safe. I promise."

"Your word doesn't mean jack, kora," Colonello grumbles from next to Harry, and he gains some scandalized looks.

Much to Harry's shock, Byakuran nods in agreement. "Great job, Colonello-kun! Now you know the 'perfectly safe' part of my introduction is a lie! Yay! Or rather, they'll be safe for another month or so. Then we'll start getting into tripwire and ropes."

Several people exchange horrified looks with their friends.

"Oh, don't worry your cute little faces!" Byakuran says, amused. "I'm not allowed to _kill_ you. Or permanently maim you."

Colonello rolls his eyes. "To you, permanently maiming somebody is cutting off all of their limbs, kora."

"Eh? Colonello-kun, don't be so violent. And don't disrupt my class or I'll have you run twenty miles around the Quidditch pitch."

Harry feels the blood drain out of his face. Running twenty miles is their punishment?

"Ah, no, no," Byakuran exclaims, reading the looks on their faces. "Only for our beloved Arcobaleno. The rest of you can't handle running half a mile, let alone twenty."

The rest of the class visibly relaxes.

"So, that's why we're going to change that!" Byakuran claps, smiling widely. "Since we're going to be doing this wonderful thing called _physical exercise,_ wands away!"

At this, Hermione raises her hand.

"Yes, Granger-san?"

She recoils briefly at Byakuran knowing her name but shakes it off quickly. "How are we supposed to learn any magic without our wands?" she asks skeptically. "And what will we be doing for OWLs?"

The Professor smirks. "Who said I was ever going to be teaching you magic?"

Harry sputters, and he isn't the only one. "How are we supposed to be in Defense Against the Dark Arts if we aren't learning magic?" Harry demands.

"Potter-san, what I am teaching you here is _Defense Against the Dark Arts_ , not magic. They are different." Byakuran raises a finger to stop the angry whispers. "I am teaching you how to defend against what you may know as the Dark Arts, and to make it so your short little lives aren't cut any shorter than they already are."

"But—!"

"But nothing. Let me ask you here—have you ever learned to _dodge_?"

The entire class, sans Colonello, shakes their heads dumbly.

"What," Byakuran says slowly, "are the teachers here teaching you? Yes, Granger-san?"

"You could just cast _Protego_ ," she replies huffily.

"And waste several seconds' time shouting your magical word and doing a fancy hand wave with your wand?" Byakuran retorts calmly, before picking up a pencil and twirling it in his fingers.

Then he throws it at Colonello, who evades it without difficulty, and much to Harry's shock, the pencil buries itself into the wall, missing the other students.

"Tell me, Granger-san; would you have had time to use a _Protego_?"

"I…"

"Alternatively, Colonello-kun could've caught it," Byakuran says thoughtfully. "But it's dangerous, catching some things, when they could explode in your fingers, or if they're on fire."

Promptly, the pencil bursts into pure white flames, its ashes falling to the ground.

"Regarding your previous question, Granger-san, about what I expect on the OWLs, I do expect all of you to be able to dodge most things _properly_. I also expect you all to know how to use a knife in more ways than one, how to use a gun, how to set traps, and some basic first aid."

Behind him, Neville whimpers slightly in fear, and Harry is honestly feeling the same way.

Byakuran smiles. "Well, I wasted more time than I'd expected. I hope you're all ready for some actual exercise! Meet me out on the Quidditch pitch, and watch out for traps!"

Harry lets his face drop on the marshmallow.

Forget Potions, Divination, History of Magic.

This class will be the hardest, even without a biased teacher!

~oOo~

 **a/n:** I hope you enjoyed this chapter! Please leave a review telling me what you think. It helps my inspiration a lot.

Also, about the Sorting Hat to take forever for Colonello, I entertained the idea of Colonello giving the Hat a very long winded lecture on _privacy._ As for Verde's almost instant choice of Ravenclaw, it's because Verde's a scientist. And his mind is full of equations and the such. So Ravenclaw.

Viper, Reborn, and Skull are in Slytherin. Viper is a moneygrubber and he's also really sly and cunning, and actually puts himself before anything else, as shown during his battle with Mukuro. Reborn is incredibly cunning and sly as well, but he isn't _smart_ as in the Ravenclaw style smart. So Slytherin for him. Skull is a Slytherin since he's incredibly ambitious.

Fon is in Hufflepuff because Hufflepuff values hard work and loyalty. He's hardworking and also quite loyal; I actually wanted him in the Ravenclaw house considering he's quite wise, but there needs to be a pair of eyes in Hufflepuff.

Colonello is a Gryffindor since he's incredibly (stupid) brave. Enough said.

Well, for the other two Arcobaleno, I'm certain Lal would get into Gryffindor as well, while Yuni is certainly a Hufflepuff. We get another Slytherin with Byakuran.

Do you agree with the House Placements?


	3. Chapter 3

**Title:** Marshmallow Addiction

 **Rating:** T

 **Genres:** Humor, Friendship, Romance, Adventure, mild Hurt/Comfort and Angst

 **Summary:** The new DADA teacher is weird. He has a marshmallow addiction. He's ridiculously misleading. He loves teasing. He… he's not even teaching them magic! Dumbledore might've wondered if Dolores Umbridge was a better choice for the DADA teacher if it weren't for the fact that he picked Byakuran because of aforementioned traits. (The transfer students aren't any better.) TYL

 **Pairings:** 10069100, 2759, XS, R56, 18D, B26; others undecided.

 **Warnings:** Swearing, violence, hilarity in general, crude humor, spoilers, post-manga, possible OOC, _Byakuran_ , TYL, the works.

*Happy late birthday, Gokudera!

~oOo~

The next morning, Byakuran spots a few of the Arcobaleno heading to the Owlery.

How…

Suspicious.

He completely ignores it.

~oOo~

A week later, on a Friday, Byakuran (and the school) learns why Viper had sent a letter.

~oOo~

Byakuran pops another marshmallow in his mouth as he perches in his chair at the staff table. This week's been _amazingly_ fun, what with terrorizing—ahem, teaching—his victims—ahem, students and all. And the Supervisor, Dolores Umbridge, hasn't arrived yet, which is _great_ … especially since she's over a week late.

He's just about to reach for some pudding when the doors to the Great Hall are promptly kicked down.

"VOOOOOOOOOOOOIIIIII! MAMMON YOU BASTARD, MAKING US COME ALL THE WAY FROM FUCKING JAPAN!"

Viper stands up calmly and glides (yes, glides) towards the people causing the ruckus. "I'm glad you're here. Now hand it over."

"I want a levy tax," Bel pipes up cheerfully. "After all, the prince came here to see you, Mammon~"

"Hell no," Viper growls. "I'm not about to waste any of my precious money on retards like you."

"Ushishishi… you did _not_ just call the prince a retard," Bel says dangerously.

"Calm down, Bel-senpai." To this, Bel promptly shoves the knife he'd been fingering into Flan's hat. "Ow," he drones monotonously.

Squalo, in the meantime, is poking his head out of the door. "VOOOOOOOOOIIIII! BOSS! GET YOUR LAZY ASS IN HERE!"

The sound of glass shattering followed by a shout of "I DON'T TAKE ORDERS FROM TRASH" is enough for anyone to wince.

Squalo withdraws, looking furious, with shards of glass in his hair. Blood runs from a few tiny cuts on his face.

"I HATE YOU SHITTY BOSS!"

"SO DO I!"

"GET YOUR ASS IN HERE AS WELL, LEVI! LUSSURIA DON'T YOU _DARE_ SHOW YOUR FUCKING GAY FACE IN HERE!"

Byakuran, through the corner of his eye, spots Colonello pulling something from under the table.

 _BANG!_

Hogwarts's walls gain another hole.

The Varia are briefly silent.

"What the actual hell are you assholes doing here, kora?" Colonello shouts, holding a gun and standing. "Viper this is your fault, isn't it, kora!"

Viper turns to Colonello calmly. "Fault? Is this a bad thing?"

"Of _course_ it is, you idiot," Verde speaks up from the Ravenclaw table, looking bored as always as he fiddles with some parts in his hands. "They're the fucking _Varia_. That's enough explanation."

Viper looks offended. " _I'm_ part of the Varia as well, Verde."

"So? You're also an Arcobaleno."

Viper officially loses the argument. Well, it's not like many can actually argue with Verde and win, anyways.

Byakuran smiles. "Ah, Flan-kun!" The poker faced Mist Guardian turns. "Is, by any chance, Mukuro coming anytime soon?"

"Pineapple-shishou says he might," Flan replies. "He claims it's only because he wants to scare the children here but I think it's actually because he wants to see you."

"Aww, how sweet of him." Byakuran smirks. "But I'm certain he only wants to come so he can try and kill me again."

"That too," Flan concedes.

McGonagall recovers first. "Albus! This is an outrage! Who are these people?"

Albus smiles his grandfatherly smile at McGonagall. "Why, they're the Varia, a separate branch of the Vongola. Please do not worry."

Viper heads towards the staff table, having wrestled a fistful of cash from a hesitant Bel. "Here," Viper says monotonously, shoving a few bills in Albus's face. "The rest of the Varia need a place to stay for a week to a month while the old headquarters is being fixed. It was destroyed when Squalo tried to use the kitchen and ended up burning the place down."

In the background, Squalo, Xanxus, and Levi have a shouting match.

Albus declines the cash. "Ah, that's easily arranged!" He claps his hands together once. "I'll have a few extra rooms set up later."

"Thank you," Viper replies before heading off to the Slytherin table, keeping the money and counting it quietly.

"But Squalo-chan, just let me in!"

"HELL NO LUSSURIA! YOU'LL MENTALLY SCAR EVERY SINGLE PERSON IN THAT ROOM!"

"HAHA, TRASH! YOU CARE FOR OTHER TRASH'S MENTAL HEALTH—THAT'S WHAT TRASH DOES!"

"SHUT UP SHITTY BOSS!"

 _Crash_.

"GODDAMMIT WHERE THE HELL DO YOU GET ALL THOSE WINE GLASSES SHITTY BOSS?!"

"I always keep a whole bunch on me so I can deal with _TRASH LIKE YOU_!" Xanxus roars back.

"Can we save the lovers' spat for later?" Byakuran calls, putting another marshmallow in his mouth. "You're scaring the children."

" _Lovers' spat_?" Squalo sputters.

Xanxus steps in, looking murderous. Byakuran is not bothered in the least. "Do you want to die today, scum?"

Byakuran shrugs. "Nope. You _can't_ kill me."

There _is_ another him where he died a few months ago because Xanxus went on a rampage… but that was under different circumstances.

The Varia boss growls. "You wanna bet?"

"Tsunayoshi-kun couldn't kill me in _many_ different worlds. What makes you think you can kill me?" Byakuran reaches for the pudding.

"Boss!" Lussuria enters the Great Hall. "Don't pick a fight with Byakuran-chan, he's taken already! And so are you!"

Levi follows after. "DO WHAT YOU WANT BOSS!"

Byakuran's hand freezes in midair as it's reaching for the pudding. He blinks once, twice, and then four times.

"Lussuria," Byakuran says very slowly, "what are you wearing?"

Lussuria pouts. "We were on a job, and one of us had to be an attractive girl, and one of us had to be an ugly girl. I, for some reason, was nominated for the latter."

"Squalo-kun. Get Lussuria out and changed. I need mind bleach."

"I DON'T TAKE ORDERS FROM YOU, STUPID MILLEFIORE ASSHOLE!"

"I'm not part of the Millefiore, Squalo-kun. Not anymore, at any rate. And you'd be doing all of us a favor."

"I'm not unattractive!" Lussuria complains.

"Please get out, Lussuria-chan."

"…Fine…" Dejected, Lussuria leaves the Great Hall, and immediately a lot of the students sag in relief. Some of them are keeping hands over their eyes and some have assumed the fetal position.

At last, Byakuran manages to get his pudding. It tastes wonderful. Though it would be far better if Xanxus and Squalo aren't glaring daggers at him.

"Ushishishi…" Byakuran raises an eyebrow as he spots Bel stalking around the tables, grinning widely while Flan trails behind him. Students cringe away in fear, probably because Bel's playing with knives.

Many of the students leave hastily, probably scared of the Varia while the Arcobaleno look amused, save Verde.

"Albus, I think you should show them their rooms now," Byakuran calls to the Headmaster, looking quite amused. "They look cranky."

" _CRANKY_? I'll show you cranky, you piece of shit!"

"VOIII! WHAT THE HELL? I AIN'T CRANKY! I'M JUST PISSED OFF!"

"Ushishishi… the prince is _never_ cranky… now come over here so I can cut your throat."

"Roar. I'm so cranky," Flan deadpans.

"IF THE BOSS IS CRANKY THEN I AM AS WELL!"

"Wah! Why are you all so cranky?"

"Cranky sounds weird now," Byakuran frowns. "Just go to bed."

Albus laughs slightly. "We have some rooms upstairs, I'll lead you there…"

The Varia, sans Viper, follow the Headmaster up, grumbling and glaring at Byakuran, who merely waves cheerfully and polishes off the last of his pudding.

~oOo~

The next morning, the school is in for a surprise when Ryohei kicks down the just repaired door during breakfast.

"Ah! Ryohei, kora!" Colonello cheers. "Did you bring the stuff, kora?"

"Yes, to the extreme!" Ryohei proclaims before brandishing a huge box and then marching to Colonello and passing it to him. "Falco is great company to the extreme!" Said falcon nips Ryohei's ear affectionately.

Byakuran doesn't hear Colonello's reply but he sees Colonello rip the top of the box with glee like a child opening a Christmas present and he actually hears a _squeal_ of joy.

The students who peer inside pale drastically and Byakuran is able to spot what's inside from his seat.

Guns, grenades, bombs—the works.

"Thanks _so much_ , kora!" Colonello carefully reseals the box. "It must've been some trouble, going from America to Italy to here, kora. I appreciate it, kora."

"It's no problem to the extreme, shishou!" Ryohei exclaims. "America and Italy are wonderful places to the extreme! Gelato is amazing to the extreme!"

Suddenly the other door is slammed open. "Ryohei-chan!" Lussuria cries. "I've missed you!"

"The Varia are here?" Ryohei asks Colonello.

Colonello grimaces and nods. "Blame Viper, kora."

"LUSSURIA! IT'S TOO DAMN EARLY FOR YOUR ANTICS!" Squalo shouts angrily, and glass shards are caught in his hair. Then he spots Ryohei and scowls. "WHERE'S THE SWORD BRAT?!"

"You mean Yamamoto-kohai? He's in Japan, visiting Namimori to the extreme!" Ryohei exclaims.

Squalo's scowl deepens. "DAMN! I WANTED TO SPAR!"

"Why're you so damned loud, trash?!" Xanxus snaps, coming up behind Squalo with Levi behind him. Then he spots Ryohei. "What the hell is the sun doing here?"

Byakuran shoves another marshmallow in his mouth. Watching the Varia is always better than watching television…

The other teachers are staring with mixtures of horror, disapproval, and fear.

"I live with these guys." Byakuran answers the unasked question, reaching for some toast.

The teachers look at him with no little amount of sympathy.

"And often," Byakuran continues, acting oblivious, "I cause the problems."

Ryohei waves at Colonello. "I'm leaving to the extreme now! I have a flight to Namimori soon!"

"Say hello to Yamamoto for me, kora!"

Ryohei nods before exiting.

Byakuran spots Flan entering and waves him over. The Mist Guardian trudges over.

"Here." Byakuran passes Flan a sheet of paper detailing the directions to the kitchens. Flan reads it over and nods. "Tell the others, so we don't have to deal with the Varia every day."

"Okay." Flan walks back to the Varia and shows them the directions and soon the Varia hustle out.

"They'll be eating in the kitchens now," Byakuran announces cheerfully. "Hopefully Squalo doesn't get anywhere near the stove."

~oOo~

Thankfully for Hogwarts, nobody arrives the next week, but the Varia is enough for anybody to throw a fit. Oddly enough, Umbridge hasn't arrived yet…

Perhaps it's the letter Tsunayoshi-kun sent to the Minister of Magic a few weeks back…

Sunday morning, and Byakuran has just finishing grading his students on their (poor) performances during his class, setting the last of the papers aside in favor for some waffles.

He looks up just as the door is opened and Byakuran pretends to drop his fork and pick it up as a trident buries itself in the wall behind him.

"Why hello there, Mukuro!" Byakuran exclaims, smiling widely.

"Kufufu… hello there, Byakuran," Mukuro replies, wearing a matching smirk. He tosses a package at the Ravenclaw table, and Verde catches it, opening it and peering inside. "Sorry I'm late. I was busy eliminating a group of yakuza in Namimori."

Byakuran notices that Mukuro is favoring his left leg and calls him out on it. "Wow, Mukuro. Either you were careless, or you're simply incompetent if a group of _yakuza_ managed to gash your leg."

Mukuro's smile turns forced. "Kufufu… Says the one working a job teaching a group of children. Would you like for me to prove to you exactly how competent I am and how incompetent _you_ are?"

"I would love to," Byakuran replies, getting up and dusting himself off.

"Pineapple-shishou, Byakuran, continue your lovers' spat later, please." Flan chooses this inopportune time to interrupt by opening the door quietly.

Mukuro and Byakuran's heads swivel towards Flan, and Byakuran feels a tic developing under his eye.

"Flan-kun. Your assumptions on our relationship is incorrect. Lovers, really?"

"I'm not a fucking _pineapple_ , you incompetent apprentice," Mukuro growls.

"Of course you aren't," Byakuran says breezily. "But you must be at least _related_."

Byakuran spots a tic on Mukuro's left temple. "You must be stupid, considering that humans and plants cannot be related. And I have never been reincarnated as a fucking _plant._ "

"Are you sure? You must at least look up to pineapples to style your hair after them."

Mukuro smiles painfully. "You must at least look up to marshmallows to dye your hair after them."

"Shishou, Byakuran, I think you two should stop arguing," Flan drones.

Mukuro and Byakuran completely ignore the Varia's Mist. "Ah, my hair is natural."

"So is mine."

"Ha! So you _are_ related pineapples!"

"You're a cannibal then. You eat marshmallows all the time!"

"Oi, pineapple freak, marshmallow face. Stop arguing _right now,_ or else I _will_ call Juudaime _._ "

Byakuran and Mukuro freeze, and Byakuran wonders how he missed Gokudera's presence.

"Kiss and make up. Note, I said make _up_ and not make _out_."

"Are you insinuating something, Hayato-kun?" Byakuran asks, raising an eyebrow.

"Yes. Pineapple freak, you can _go_ now. You two can continue your lovers' spat once Byakuran comes home."

"Hey, how come Hayato-kun can call you pineapple freak but I can't call you pineapple?" Byakuran complains.

"Because at least he calls you marshmallow face and the skylark 'biting and BDSM fetish asshole'."

Gokudera glares. "Out. Right now. Before I bust out the dynamite and send you home via explosion."

"Yes, yes." Mukuro rolls his eyes. "I'll kill you when you get back."

"You're welcome to try," Byakuran calls after him as the door shuts, waving cheerfully.

Then he sits back down and takes a bite out of syrup soaked waffles.

~oOo~

 **a/n:** Woohoo! Guest appearances from the Varia, Ryohei, Mukuro, and Gokudera! Gokudera had to make it in, since it was his birthday four days ago! Happy birthday, Gokudera-kun!


End file.
